title: The concentrations of some gut polypeptides are elevated during lactation in ruminants.
abstract: Circulating concentrations of both glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1(7-36)amide (GLP-1) were determined in dry and lactating sheep. Both polypeptides were significantly higher in lactating animals compared with dry. The half-life of both in plasma was determined by intravenous injection of GIP or GLP-1 in both dry and lactating animals, but neither peptide showed a significantly different value during lactation. Thus, the increased circulating concentrations during lactation must result from increased secretion, probably resulting from the increased feed intake during lactation. Serum insulin concentrations were significantly lower during lactation, which poses the question of how lactating animals maintain lower circulating insulin levels in the presence of higher levels of insulinotropic agents.
authors.affiliation: Hannah Research Institute, Ayr, Scotland. faulknera@main.hri.sari.ac.uk
authors.forename: A
authors.initials: A
authors.lastname: Faulkner
authors.forename: P A
authors.initials: PA
authors.lastname: Martin
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism; D005227:Fatty Acids / Q000097:blood / Q000378:metabolism; D005260:Female; D005749:Gastric Inhibitory Polypeptide / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D005934:Glucagon / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D052216:Glucagon-Like Peptide 1; D007328:Insulin / Q000097:blood / Q000378:metabolism; D007774:Lactation / Q000378:metabolism*; D010446:Peptide Fragments / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D011498:Protein Precursors / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D012756:Sheep / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D005227:Fatty Acids; D007328:Insulin; D010446:Peptide Fragments; D011498:Protein Precursors; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D005934:Glucagon